This invention relates to an engine protection device. In particular, it relates to a novel engine protection device which does not require an outside power source such as compressed air, but can operate off the engine itself.
Engine protection devices have been described in prior patents of the applicant, namely U.S. Pat. No. 4,485,781 and U.S. Pat. No. 4,729,355. In U.S. Pat. No. 4,485,781, a fluid or air pressure activated cylinder in series with the engine throttle rod is used to limit or stop the available engine speed, if the engine oil pressure falls to a predetermined level or engine coolant temperature rises above a predetermined level. U.S. Pat. No. 4,729,355 includes an oil pressure regulator having a fluid release system including a reduced pressure feedback system to vary the return pressure to a higher pressure after initial operation at a lower pressure. In both of these patents, either pressurized fluid or a vacuum source is required.
One object of the present invention is to provide an engine protection device which does not require an outside pressure or vacuum source but can be operated from the engine itself.
Other objects and advantages of the invention will be apparent from the descriptions and claims which follow taken together with the appended drawings.